Modern Physics
The first explosion of an atomic device in India was carried out in the state of
  • Jammu and Kashmir
  • Manipur
  • Nagaland
Explanation: The first explosion of an atomic device in India was carried out in the state of (A) Rajasthan at Pokhran on 18 May 1974. It was called "Smiling Buddha."
Which of the following will deflect in electric field?
  • X-rays
  • Y-rays
  • Ultraviolet rays
  • Cathode rays
Explanation: Cathode rays are streams of electrons, which are negatively charged particles. Since they have charge, they get deflected in an electric field. X-rays, gamma (γ) rays, and ultraviolet rays are electromagnetic waves and have no charge, so they do not get deflected in an electric field.
Cathode rays can be deflected by
  • Magnetic field
  • Electric fields
  • Both electric and magnetic fields
  • None of the above
Explanation: Cathode rays are streams of electrons, which are negatively charged particles. Since they have charge, they can be deflected by both electric and magnetic fields according to Lorentz force principles.
After pumping process in laser, ______
  • No atoms are available in the excited state
  • The number of atoms in the ground state is equal to the number of atoms in the excited state
  • The number of atoms in the ground state is greater than the number of atoms in the excited state
  • The number of atoms in the excited state is greater than the number of atoms in the ground state
Explanation: In a laser (Light Amplification by Stimulated Emission of Radiation), after the pumping process, a condition called population inversion is achieved. This means that more atoms are in an excited state than in the ground state, which is essential for the stimulated emission of photons and laser action.
Chokes used in wireless receiver circuits are called
  • audio frequency chokes
  • radio frequency chokes
  • high frequency chokes
  • both b and c
Explanation: Chokes used in wireless receiver circuits are designed to block high-frequency AC signals while allowing DC or lower-frequency signals to pass. These chokes are specifically called Radio Frequency (RF) Chokes or High-Frequency Chokes, as they prevent unwanted high-frequency interference in circuits.
At resonant frequency of RLC series circuit impedance of the circuit
  • and current becomes minimum
  • and current becomes maximum
  • is minimum and current becomes maximum
  • is maximum and current becomes minimum
The mutual induction is very large, if the two coils are wound on
  • copper frame
  • soft iron core
    • Explanation: Soft iron increases the magnetic flux linkage between the coils, enhancing mutual induction.